Upload
123habib123fikri
View
222
Download
0
Embed Size (px)
Citation preview
8/10/2019 Risk Assessment of Ship Collision with Platform
1/40
COLLISION RISK ASSESSMENT OF VESSEL
AND PLATFORM: CASE STUDY OF
PLATFORM CONSTRUCTION PROJECT AT
BINTUNI BAY WEST PAPUA
Presented by: Muhammad Habib Chusnul FIkri
Department of Marine Engineering
Faculty of Marine Technology
Institut Teknologi Sepuluh Nopember
8/10/2019 Risk Assessment of Ship Collision with Platform
2/40
Purpose
- To identify impactconsequence
- To identify collisionfrequency
- To measure risk of
collision
- To give justification ofmitigation effort toreduce risk
2
8/10/2019 Risk Assessment of Ship Collision with Platform
3/40
Description of FacilityThe closest distancebetween platforms tothe center of theshipping lane is around3000 m.
Platform A
Platform B
3
8/10/2019 Risk Assessment of Ship Collision with Platform
4/40
MethodologySTART
PROBLEM
ANALYSIS
SCENARIO
DEVELOPMENT
LITERATURE
STUDY
IMPACT
CONSEQUENCE
SIMULATION
USING FEM
COLLISION
FREQUENC
CALCULATION
EMPIRICAL
IMPACT
CONSEQUENCE
CALCULATION
VERIFIED ?nono
RISK
ACCEPTABLE
?
yes
CONCLUSION AND
RECOMMENDATION
yes
MITIGATION
no
FINISH
4
8/10/2019 Risk Assessment of Ship Collision with Platform
5/40
Passing Vessel Collision Geometry FCP = N x Fd x P
Where:
N = Total traffic in the lane (vesselmovements/year).
Fd = Proportion of vessels that are inthe part of the lane directedtowards the platform.
P = Probability of Collision per passing
vessel
Fd = D x [exp (-k2/2)]/ (2)
5
Human error Ship
control
failure
Platform Radar
Beacon Failure
80%
Ship Radar
Failure
15.4% Prop. system
failure
8% 2%
Prob of
Collision/passing8% Nav. system
failure
83.1%
1.66%
8/10/2019 Risk Assessment of Ship Collision with Platform
6/40
Drifting Vessel Collision The mathematical equation is presentedas follow
FCD = Nb x P x D/BL
Where:
Nb = total traffic in the box(vessels/year)
P = breakdown or collisionprobability in box per passingvessel
D = collision diameter
BL = box length perpendicular to
wind direction
6
Wind/current
blow to
platform
10%
Human error Ship
control
failure
Platform Radar
Beacon Failure
80% Prob of
Collision/
passing8% Nav. system
failure
83.1%
0.17%
Ship Radar
Failure
15.4% Prop. system
failure
8% 2%
8/10/2019 Risk Assessment of Ship Collision with Platform
7/40
Visiting Vessel Collision
A = arctan [(D1 + D2)/2L]
where:
A = angle subtended byplatform (rad)
D1 = width of tanker normalto drift track
D2 = width of platformnormal to drift track
L = initial distance oftanker from platform
7
8/10/2019 Risk Assessment of Ship Collision with Platform
8/40
Failure Rate Data
8
Below data are used. These data are cumulative valuse for 376 observedobjects of ships
Source: Kiriya, Nobuo. Statistical Study on Reliability of Ship Equipment andSafety Management
=
8/10/2019 Risk Assessment of Ship Collision with Platform
9/40
Impact Energy
There are two criteria of impact level as follows:
Global failure; very large impact collision, resulting in a
very massive deformation that led to failureof structure and facility shutdown
Local failure; produced impact has exceeded the powerof material elasticity, resulting in permanentdeformation. However, failure of structurestill can be avoided so as facility shutdown isnot necessary.
= 1
2
k=1.1 for head on collision
K=1.4 for drifting collision
9
8/10/2019 Risk Assessment of Ship Collision with Platform
10/40
Platform Structure
Structure Detail
1. Outer Leg: 1600 x 60 WT mmSteel
2. Inner Leg : 1372 x 38 WTmm concrete pile
3. Braces : 762 x 25 WT
mm Steel
10
8/10/2019 Risk Assessment of Ship Collision with Platform
11/40
Dent DepthThe denting of a tubular is described by the equation below. This equation forimpact energy (E), obtained from integration of the impact force as a function ofthe dent depth, are:
[Reference: Visser Consultancy. Ship collision and capacity of brace members offixed steel offshore platform. 2004]
11
8/10/2019 Risk Assessment of Ship Collision with Platform
12/40
Inner Concrete Pile Energy AbsorptionThere are concrete piles inside every legs platform structure with particulardimension. There is a gap between inner pile outer diameter and platform leginner diameter. Once the dent produced by impact energy is more than this
value, there is a value of absorbed energy by concrete pile which is calculated byfollowing equation:
Y = concrete crushing strength, taken as 120 MPa
Maksimum absorbed energy = 0.95 MJ
[Reference: DNV RPF107, sub 4.6.1]
12
8/10/2019 Risk Assessment of Ship Collision with Platform
13/40
8/10/2019 Risk Assessment of Ship Collision with Platform
14/40
Head-on Collision for External Vessel (1)
Scenario:
1. Human error by standby
watching officer2. Failure of platform location
identification by navigationsystem
3. Failure of propulsion system-deadship
4. Failure of determining theshipping lane, causing theship take voyage lane nearplatform (within 500 mprohibited radius)
Ship is engaged in voyage from Maluku sea,entering bintuni bay towards bintuni port (fromsouth to north)
14
8/10/2019 Risk Assessment of Ship Collision with Platform
15/40
Head-on Collision for External Vessel (1)
No
1
21152
Fishing Vessel 10
Crew boat/Pass engger ferry 8.2
Type of Vessel Annual Traffic Breadth (m)
15
A 8% 8% 8% 8% 8%
B 8% 8% 8% 8% 8%C 15.4% 15.4% 15.4% 15.4% 15.4%
D 80% 80% 80% 80% 80%
E 83.1% 83.1% 83.1% 83.1% 83.1%
H 2880 3456 4032 4608 5184
J 1709 1709 1709 1709 1709
K 0.01% 0.01% 0.01% 0.01% 0.01%
L 1.36 1.36 1.36 1.36 1.36
N 2320 2320 2320 2320 2320
O 1709 1709 1709 1709 1709
P 0.223 0.267 0.312 0.357 0.401
0.47%
5 th
five
year
2%
0.47% 0.47% 0.47% 0.47%
1.66%
4040
1.66% 1.66% 1.66%
2 nd
five
year
3 th
five
year
4 th
five
year
2%
G
40
Nav System Failure = 1-(1-A)(1-B)
Human error
Ship Control Failure = 1-(1-C)(1-D)
Collision Diameter = length of platform +
w idth of passing Vessel40 40
1.66%
2% 2%2%
Ship Radar Failure
F
I
Platform Radar Beacon Failure
This calculation is done for 25 years
li fetime of pla tform, by consi dering traffic
increment by 5% per year
1 st
five
year
M
standard deviation in meter
f(A ) = (0.5)exp(-k^2/2)/J
Annual Passing Vessel
Prop. system failure
k = distance/standard deviation
Fd = proportion of passing vessel crash
tow ard platform = K x I
Width of Shipping Lane (m)
Annual Frequency of Collision = GxHxM
Distance betw een Centerlane and platform
Prob. Of Collission/passing = CxExF
8/10/2019 Risk Assessment of Ship Collision with Platform
16/40
Head-on Collision for External Vessel (2)
No
1
21152
Fishing Vessel 10
Crew boat/Pass engger ferry 8.2
Type of Vessel Annual Traffic Breadth (m)
16
A 8% 8% 8% 8% 8%
B 8% 8% 8% 8% 8%
C 15.4% 15.4% 15.4% 15.4% 15.4%
D 80% 80% 80% 80% 80%
E 83.1% 83.1% 83.1% 83.1% 83.1%
H 2880 3456 4032 4608 5184
J 2333 2333 2333 2333 2333
K 0.01% 0.01% 0.01% 0.01% 0.01%
L 1.62 1.62 1.62 1.62 1.62
N 3789 3789 3789 3789 3789
O 2333 2333 2333 2333 2333
P 0.110 0.132 0.154 0.176 0.197
40
0.23%
Width of Shipping Lane (m)
Annual Frequency of Collision = GxHxM
Collision Diameter = length of platform +
w idth of passing Vessel40 40
2% 2%
Prob. Of Collission/passing = CxExF 1.66% 1.66%
5 th
five
year
2%
Distance betw een Centerlane and platform
40
standard deviation in meter
f(A) = (0.5)exp(-k^2/2)/J
k = distance/standard deviation
Fd = proportion of passing vessel crash
tow ard platform = K x I0.23% 0.23% 0.23% 0.23%
40
Prop. system failure 2%
Platform Radar Beacon Failure
Annual Passing Vessel
1.66%1.66% 1.66%
2%
Ship Radar Failure
Nav System Failure = 1-(1-A)(1-B)
3 th
five
year
Human error
Ship Control Failure = 1-(1-C)(1-D)
4 th
five
year
1 st
five
year
This cal culation is done for 25 years
lifetime of platform, by considering traffic
increment by 5% per year
2 nd
five
year
F
G
I
M
8/10/2019 Risk Assessment of Ship Collision with Platform
17/40
Head-on Collision for Internal Vessel (1)
17
No
1
2
3 General Cargo 104 22
23
Type of Vessel Annual Trafffic Breadth (m)
LNG Tanker 105 46
Condensate Tanker 23
A 8% 8% 8% 8% 8%
B 8% 8% 8% 8% 8%
C 15.4% 15.4% 15.4% 15.4% 15.4%
D 80% 80% 80% 80% 80%
E 83.1% 83.1% 83.1% 83.1% 83.1%
H 580 696 812 928 1044
J 2333 2333 2333 2333 2333
K 0.01% 0.01% 0.01% 0.01% 0.01%
L 1.62 1.62 1.62 1.62 1.62
N 3789 3789 3789 3789 3789
O 2333 2333 2333 2333 2333
P 0.042 0.050 0.059 0.067 0.076
76
0.44%
5 th
five
year
2%
1.66%
Platform Radar Beacon Failure
Nav System Failure = 1-(1-A)(1-B)
Human error
Ship Control Failure = 1-(1-C)(1-D)
3 th
five
year
4 th
five
year
This calculation is done for 25 years
li fetime of pl atform, by consi dering traffic
increment by 5% per year
1 st
five
year
2 nd
five
year
Ship Radar Failure
1.66%
Prop. system failure 2% 2% 2% 2%
Prob. Of Collission/passing = CxExF 1.66% 1.66% 1.66%
76 76
0.44% 0.44% 0.44%
standard deviation in meter
Annual Passing Vessel
Collision Diameter = length of platform +
w idth of passing Vessel76 76
Distance betw een Centerlane and platform
Width of Shipping Lane (m)
Annual Frequency of Collision = GxHxM
f(A) = (0.5)exp(-k^2/2)/J
k = distance/standard deviation
Fd = proportion of pass ing vessel crashtow ard platform = K x I
F
G
I
M 0.44%
8/10/2019 Risk Assessment of Ship Collision with Platform
18/40
8/10/2019 Risk Assessment of Ship Collision with Platform
19/40
Drifting Collision for External Vessel (1)
Scenario:
1. Human error by standby
watching officer2. Failure of platform location
identification by navigationsystem
3. Failure of propulsionsystem-deadship
4. Ship became adrift becauseof wind and current whilelost control
5. Collision happened becauseof ship already nearby
platform (within 500 mprohibited radius)Ship is engaged in voyage from Maluku sea,
entering bintuni bay towards bintuni port (fromsouth to north)
19
8/10/2019 Risk Assessment of Ship Collision with Platform
20/40
8/10/2019 Risk Assessment of Ship Collision with Platform
21/40
D if i C lli i f I l V l (1)
8/10/2019 Risk Assessment of Ship Collision with Platform
22/40
Drifting Collision for Internal Vessel (1)
22
No
1
2
3
105
23
General Cargo 104 22
Condensate Tanker 23
Type of Vessel Annual Trafffic Breadth (m)
LNG Tanker 46
A 8% 8% 8% 8% 8%
B 8% 8% 8% 8% 8%
C 15.4% 15.4% 15.4% 15.4% 15.4%
D 80% 80% 80% 80% 80%
E 83.1% 83.1% 83.1% 83.1% 83.1%
H 580 696 812 928 1044
J 10% 10% 10% 10% 10%
K1064 1064 1064 1064 1064
L 7.14% 7.14% 7.14% 7.14% 7.14%
M 0.069 0.083 0.096 0.110 0.124
F
G
This cal culation is done for 25 years
li fetime of pl atform, by consi dering traffic
increment by 5% per year
Ship Radar Failure
Probability of w ind/current tow ard platform
Width of Collision Lane (m)Prob of Vessel inside Collision Lane
Annual Frequency of Collision
Annual Passing Vessel
Collision Diameter = length of platform +
w idth of passing Vessel7676I 76 76 76
2% 2% 2%
0.17% 0.17%
5 st
five
year
2%
0.17%
2%
Probability of Collision per passing vessel 0.17%
Nav. system failure
Human error
Ship control failure
Prop. system failure
4 st
five
year
Platform Radar Beacon Failure
1 st
five
year
2 st
five
year
0.17%
3 st
five
year
D if i C lli i f I l V l (2)
8/10/2019 Risk Assessment of Ship Collision with Platform
23/40
Drifting Collision for Internal Vessel (2)
23
No
1
2
3
Offshore Supply Vessel 116 24.4
Multi Purpose Support Vessel 2 18.8
Type of Vessel Annual Trafffic Breadth (m)
Landing Craft Transport 10 24
A 8% 8% 8% 8% 8%
B 8% 8% 8% 8% 8%
C 15.4% 15.4% 15.4% 15.4% 15.4%
D 80% 80% 80% 80% 80%
E 83.1% 83.1% 83.1% 83.1% 83.1%
H 320 384 448 512 576
J 10% 10% 10% 10% 10%
K 879 879 879 879 879
L 6.19% 6.19% 6.19% 6.19% 6.19%
M 0.033 0.039 0.046 0.053 0.059
2 st
five
year
Platform Radar Beacon Failure
3 st
five
year
This calculation is done for 25 years
lifetime of platform, by considering traffic
increment by 5% per year
1 st
five
year
54.4
Probability of w ind/current toward platform
Width of Collision Lane (m)
Prob of Vessel inside Collision Lane
Annual Frequency of Collision
54.4Collision Diameter = length of platform +
w idth of passing Vessel54.4 54.4
Human error
Ship control failure
Prop. system failure 2%
Ship Radar Failure
Nav. system failure
2%2% 2%2%
4 st
five
year
0.17%
54.4
F
G
I
Annual Passing Vessel
Probability of Collision per passing vessel 0.17% 0.17% 0.17% 0.17%
5 st
five
year
Vi i i V l C lli i
8/10/2019 Risk Assessment of Ship Collision with Platform
24/40
Visiting Vessel Collision
D1 62 62 62 62
D2 30 30 30 30
L 50 60 70 80
A 0.744 0.654 0.581 0.522
0.118 0.104 0.093 0.083
Distance w here maneuvering begins
Length of Vessel
Offshore Supply Vessel
Maneuvering dis tance is used a s cal culation variabe l to find out how
near the maneuvering di stance considerably sa fe
1.184 1.041 0.925 0.831
Length of Platform
Angle of maneuvering (radian)
Probability of Collision per visit
Annual probability of collision
Multi Purpose Support Vessel
D1 92.4 92.4 92.4 92.4
D2 30 30 30 30
L 140 150 160 170
A 0.412 0.387 0.365 0.346
0.066 0.062 0.058 0.055
Annual probability of collision 1.115 1.048 0.935
Probability of Collision per visit
Length of Vessel
Length of Platform
Distance w here maneuvering begins
Angle of maneuvering (radian)
Mane uvering distance is us ed as calculation varia bel to find out how
near the maneuvering dis tance consi derably safe
0.988
24
8/10/2019 Risk Assessment of Ship Collision with Platform
25/40
CollisionConsequence
Results at Pile Leg
8/10/2019 Risk Assessment of Ship Collision with Platform
26/40
26
(m) /D
4 0.47 0.04 2% 0 0
6 1.05 0.07 4% 0.16 0.01
8 1.86 0.10 6% RUPTURE RUPTURE
10 2.91 0.13 8% RUPTURE RUPTURE
4 1.98 0.10 6% RUPTURE RUPTURE
6 4.45 0.17 11% RUPTURE RUPTURE
8 7.92 0.25 16% RUPTURE RUPTURE
10 12.37 0.34 21% RUPTURE RUPTURE
4 2.33 0.11 7% RUPTURE RUPTURE
6 5.24 0.19 12% RUPTURE RUPTURE
8 9.32 0.28 18% RUPTURE RUPTURE
10 14.56 0.38 24% RUPTURE RUPTURE4 2.67 0.12 8% RUPTURE RUPTURE
6 6.01 0.21 13% RUPTURE RUPTURE
8 10.68 0.31 19% RUPTURE RUPTURE
10 16.68 0.42 26% RUPTURE RUPTURE
4 9.32 0.28 18% RUPTURE RUPTURE
6 20.96 0.48 30% RUPTURE RUPTURE
8 37.26 0.71 44% RUPTURE RUPTURE
10 58.22 0.96 60% RUPTURE RUPTURE
4 20.59 0.48 30% RUPTURE RUPTURE
6 46.32 0.82 51% RUPTURE RUPTURE
8 82.35 1.20 75% RUPTURE RUPTURE
10 128.67 1.62 101% RUPTURE RUPTURE
Types of
Vessel
Ship
Displacement
Speed
[knot]
Fishing
boats/
Trawlers/
Small crew
200
Passenger/
Ferry850
Impact
Energy
[MJ]
1,146OSV
Landing
Craft Unit4,000
Pile Dent
[m]
Absorbed
Energy by
Pile [MJ]
Dent Depth
Multi
Purpose
Support
Vessel
8,840
Tug 1,000
Head onCollisionConsequenceson Leg
8/10/2019 Risk Assessment of Ship Collision with Platform
27/40
27
Head onCollisionConsequenceson Leg
(m) /D
4 23.29 0.52 32% RUPTURE RUPTURE
6 52.40 0.89 56% RUPTURE RUPTURE
8 93.16 1.31 82% RUPTURE RUPTURE
10 145.56 1.76 110% RUPTURE RUPTURE4 33.77 0.66 42% RUPTURE RUPTURE
6 75.98 1.14 71% RUPTURE RUPTURE
8 135.08 1.68 105% RUPTURE RUPTURE
10 211.06 2.26 141% RUPTURE RUPTURE
4 39.61 0.74 46% RUPTURE RUPTURE
6 89.13 1.27 79% RUPTURE RUPTURE
8 158.46 1.86 116% RUPTURE RUPTURE
10 247.59 2.51 157% RUPTURE RUPTURE
4 244.54 2.49 156% RUPTURE RUPTURE
6 550.20 4.27 267% RUPTURE RUPTURE
8 978.14 6.27 392% RUPTURE RUPTURE
10 1528.35 8.44 528% RUPTURE RUPTURE
Dent DepthAbsorbed
Energy by
Pile [MJ]
Pile Dent
[m]
Speed
[knot]
Impact
Energy
[MJ]
Pipelaying
Vessel10,000
Types of
Vessel
Ship
Displacement
General
Cargo14,500
Condensate
Tanker17,010
LNG Tanker 105,000
8/10/2019 Risk Assessment of Ship Collision with Platform
28/40
8/10/2019 Risk Assessment of Ship Collision with Platform
29/40
29
Drifting CollisionConsequenceson Leg (m) /D
1 1.64 0.09 6% 0.82 0.03
2 6.55 0.22 14% RUPTURE RUPTURE
3 14.74 0.38 24% RUPTURE RUPTURE4 26.20 0.56 35% RUPTURE RUPTURE
1 1.85 0.10 6% RUPTURE RUPTURE
2 7.41 0.24 15% RUPTURE RUPTURE
3 16.67 0.42 26% RUPTURE RUPTURE
4 29.64 0.61 38% RUPTURE RUPTURE
1 2.69 0.12 8% RUPTURE RUPTURE
2 10.74 0.31 19% RUPTURE RUPTURE
3 24.18 0.53 33% RUPTURE RUPTURE4 42.98 0.78 49% RUPTURE RUPTURE
1 3.15 0.14 9% RUPTURE RUPTURE
2 12.60 0.34 22% RUPTURE RUPTURE
3 28.36 0.59 37% RUPTURE RUPTURE
4 50.42 0.87 54% RUPTURE RUPTURE
1 19.45 0.46 29% RUPTURE RUPTURE
2 77.81 1.16 72% RUPTURE RUPTURE
3 175.06 1.99 124% RUPTURE RUPTURE4 311.23 2.92 183% RUPTURE RUPTURE
Types of
Vessel
Ship
Displacement
Speed
[knot]
Impact
Energy
[MJ]
Dent DepthAbsorbed
Energy by
Pile [MJ]
Pile Dent
[m]
LNG Tanker 105,000
General
Cargo10,000
General
Cargo14,500
Condensate
Tanker17,010
Multi
Purpose
SupportVessel
8,840
8/10/2019 Risk Assessment of Ship Collision with Platform
30/40
30
Head onCollisionConsequenceson Brace
(m) /D
4 0.47 0.09 12%
6 1.05 0.16 21%
8 1.86 0.23 30%10 2.91 0.31 41%
4 1.98 0.24 32%
6 4.45 0.41 54%
8 7.92 0.61 80%
10 12.37 0.82 107%
4 2.33 0.27 35%
6 5.24 0.46 60%
8 9.32 0.68 89%
10 14.56 0.91 119%
4 2.67 0.29 39%
6 6.01 0.50 66%
8 10.68 0.74 97%
10 16.68 1.00 131%4 9.32 0.68 89%
6 20.96 1.16 152%
8 37.26 1.70 224%
10 58.22 2.29 301%
Landing
Craft Unit4,000
Passenger/
Ferry850
Tug 1,000
OSV 1,146
Dent Depth
Fishing
boats/
Trawlers/Small crew
200
Types of
Vessel
Ship
Displacement
Speed
[knot]
Impact
Energy
[MJ]
Impact
8/10/2019 Risk Assessment of Ship Collision with Platform
31/40
31
Head onCollisionConsequenceson Brace
(m) /D
4 20.59 1.15 151%
6 46.32 1.97 259%
8 82.35 2.89 379%
10 128.67 3.89 511%
4 23.29 1.25 163%
6 52.40 2.14 281%
8 93.16 3.14 412%
10 145.56 4.23 555%
4 33.77 1.60 209%
6 75.98 2.74 360%8 135.08 4.02 528%
10 211.06 5.41 711%
4 39.61 1.78 233%
6 89.13 3.05 400%
8 158.46 4.47 587%
10 247.59 6.02 790%4 244.54 5.97 784%
6 550.20 10.26 1346%
8 978.14 15.05 1975%
10 1528.35 20.27 2660%
Dent DepthSpeed
[knot]
Impact
Energy
[MJ]
GeneralCargo
14,500
Condensate
Tanker17,010
LNG Tanker 105,000
Pipelaying
Vessel10,000
Multi
Purpose
Support
Vessel
8,840
Types of
Vessel
Ship
Displacement
Sim lation in 7 42 MJ impact energ
8/10/2019 Risk Assessment of Ship Collision with Platform
32/40
32
Simulation in 7.42 MJ impact energy
Rather then modeling a ship or simplification of impact energysimulation, the colliding object simplified as shown above, withparticular mass, velocity, and impact energy
Simulation in 66 77 MJ impact energy
8/10/2019 Risk Assessment of Ship Collision with Platform
33/40
33
Simulation in 66.77 MJ impact energy
This simulation aims to determine the depth of penetration of the steelstructure of the platform leg
8/10/2019 Risk Assessment of Ship Collision with Platform
34/40
Simulation in 363 52 MJ impact energy
8/10/2019 Risk Assessment of Ship Collision with Platform
35/40
35
Simulation in 363.52 MJ impact energy
This simulation aims to determine the depth of penetration of the steelstructure of the platform leg
Simulation in 741 87 MJ impact energy
8/10/2019 Risk Assessment of Ship Collision with Platform
36/40
36
Simulation in 741.87 MJ impact energy
This simulation aims to determine the depth of penetration of the steelstructure of the platform leg
Impact Analysis Result
8/10/2019 Risk Assessment of Ship Collision with Platform
37/40
Impact Analysis Result
From this analysis, it canbe concluded that
estimate value of impactenergy absorbed byplatform structure isabout 37% of totalimpact energy (kineticenergy from ship)
37
8/10/2019 Risk Assessment of Ship Collision with Platform
38/40
Conclusion
8/10/2019 Risk Assessment of Ship Collision with Platform
39/40
Conclusion
39
By adding restricted area buoy marks, with following coordinates:Coordinate 1
20 21` 29.7`` S1330 4` 48.0`` E
Coordinate 220 21` 6.7`` S
1330 4` 48.0`` E
Coordinate 320 21` 6.7`` S
1330 5` 11.0`` E
Coordinate 420 21` 29.7`` S
1330 5` 11.0`` E
8/10/2019 Risk Assessment of Ship Collision with Platform
40/40
Thank You Very Much